﻿using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;

namespace Liphofra.Mvvm.Converters
{
    /// <summary>
    /// A value converter that converts boolean to visibility values.
    /// </summary>
    public class BooleanToVisibilityConverter : IValueConverter
    {
        /// <summary>
        /// Modifies the source data before passing it to the target for display in the UI.
        /// </summary>
        /// <param name="value">The source data being passed to the target.</param>
        /// <param name="targetType">The <see cref="T:System.Type" /> of data expected by the target dependency property.</param>
        /// <param name="parameter">An optional parameter to be used in the converter logic. Can be "Invert" to invert the logic.</param>
        /// <param name="culture">The culture of the conversion.</param>
        /// <returns>
        /// The value to be passed to the target dependency property.
        /// </returns>
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            try
            {
                var boolean = (bool)value;

                if (parameter != null && parameter.ToString() == "Invert")
                {
                    boolean = !boolean;
                }

                if (boolean)
                {
                    return Visibility.Visible;
                }
                else
                {
                    return Visibility.Collapsed;
                }
            }
            catch (InvalidCastException)
            {
                return false;
            }
        }

        /// <summary>
        /// Modifies the target data before passing it to the source object.  This method is called only in <see cref="F:System.Windows.Data.BindingMode.TwoWay" /> bindings.
        /// </summary>
        /// <param name="value">The target data being passed to the source.</param>
        /// <param name="targetType">The <see cref="T:System.Type" /> of data expected by the source object.</param>
        /// <param name="parameter">An optional parameter to be used in the converter logic.</param>
        /// <param name="culture">The culture of the conversion.</param>
        /// <returns>
        /// The value to be passed to the source object.
        /// </returns>
        /// <exception cref="System.NotSupportedException">Always thrown because this conversion is not supported.</exception>
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotSupportedException();
        }
    }
}